SULFURIC ACID TREATED DATE PITS AS DIETARYINGREDIENTS IN TILAPIA (Oreochromis niloticus) DIETS

M. F. Osman, A. A. Ben Zayed. G. A. Alhadrami

Animal Production Department, Faculty of Agricultural Sciences -U.A.E. University, P.O. Box 17555 AI-Ain, United Arab Emirates

ABSTRACT

Five isonitrogenous (40% CP) and isocaloric (19 MJ/kg) diets wereformulated to investigate the utilization of acid treated date pits ascarbohydrate source for tilapia fingerlings (Oreochromis niloticus). Tilapiawith an average body weight of 6.61 :t 0.04 g were randomly stocked for42 days in self-cleaning, fiberglass tanks. Diet 1 (control) contained 30%wheat flour as the main source of carbohydrate. Wheat flour in diets 2 and 4was replaced by 50% (15% of the total diet) and 100% (30% of the totaldiet) untreated date pits, respectively. Also, treated date pits replaced 50%and 100% of the wheat flour in diets 3 and 5, respectively. Date pits wereimmersed in 70% H2 S04 for 30 min. and neutralized to pH 7 by sodiumhydroxide. Growth performance, feed conversion ratio and proteinproductive value were significantly (P<0.05) higher in fish fed diet 3,whereas fish fed diet 4 gave the lowest values (P>0.05). Fish received dietscontaining treated date pits had better productive performance values thanthat fed untreated date pits, within the same replacement percentage.Carcass analysis showed significantly (P<0.05) lower crude protein contentin fish received treated date pits compared to the groups received untreated

. date pits. Dry matter and ash content were not affected.

INTRODUCTION

Around the world in tropical and sub-tropical areas, the numbers ofdate palm trees are increased vigorously because of its suitability to begrown under arid conditions. Wasted date and date by-products arepromising non-traditional carbohydrate sources in animal nutrition.Utilization of date by-products in animal feeds was first carried out by Aliet al. (1956) for dairy cows. AI-Azzawi (1960), Afifi et al. (1966), AI-Hiti& Rous (1978) AI-Yousefet al. (1986) investigate the utilization of date by-products for broiler, Nagib et al. (1994) for layer hen and Aldosari et al.(1995) for sheep.

The use of date and date pits as fish feed source was first mentionedby Yousif et al. (1996). They found positive growth performance in all fishgroups fed diets containing date pits and were superior on that fed datepulp. Also Belal and Al Jasser (1997) found that the total replacement of

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corn starch by date by-product improve tilapia weight gain, feed conversionand protein efficiency ratio. Date pits includes high amount of crude fiber(14.40%, Yousef et al. 1996- Richter and Becker, 1956), which decreasethe utilization of other nutrients. AI-Yousef et al. (1986) reported thatsodium hydroxide treatment of date pits increased the rate of in-vitrodigestibility by solubilizing some of the cell wall. The purpose of thepresent study was to evaluate the utilization of acid treated date pits inOreochromis niloticus diets.

MATERIALS AND METHODS

Diets preparation:

Diet ingredients were obtained from the local market in Al Ain City.The Faculty of Agricultural Sciences Farm (Aloha) provided date pits. Fiveisonitrogenous (40% CP) and isocaloric (18.9 Mj/ Kg) diets were prepared.Date pits were included in the experimental diets in a rate of 0, 15, 15,30and 30% for diets 1(control), 2, 3,4 and 5, respectively. The date pits indiets 3 and 5 were immersed in 70% H2 S04 for 30 min. to remove theoutside cover and then washed-up with tap water. Date pits (untreated andtreated) were ground in 2mm-mesh sieve. Chemical analyses of treated anduntreated date pits are presented in table 1.

Table 1: Chemical analysis of date pits (% DM)

Moisture8.248.68

CP%5.905.46

EE%7.208.27

CF%31.5922.26

Ash NFE0.95 54.361.78 62.23

*) Date pits immersed in H2 S04 (70%) for 30 min.

In preparing the diets, dry ingredients were first ground to smallparticle size, then they were thoroughly mixed and water was added toobtain a 30% moisture content. Diets were passed through a mincer with0.6-mm diameter and were dried at 55° C for 16 h using a dry oven. Afterdrying the diets were broken up and sieved into convenient pellet size. Alldiets were frozen (-15° C) until feeding.

Composition and chemical analysis of the experimental diets arepresented in table 2.

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2) Vitamin mi~ture: Shrimp tonic, N Marine East. Co. Ltd, Thailand.

Experimental fish:

Oreochromis ni/oticus fingerlings (6.6 gJ fish) were obtained fromthe fish stock of the fish culture laboratory. Fish were acclimated for oneweek indoor 10-liter fiberglass tanks at a rate of 1 fish! 1 liter and fed thecontrol diets (40% CP and 19 Mj/ Kg). Three tanks were used pertreatment. Fish from each tank were weighed at the beginning of theexperiment, every 2 weeks and at the end of the feeding trial. The fish werefed the experimental diets for 6 weeks twice a day, 6 days per week at alevel of 5% of the body weight per day. At initiation and end of the feedingtrial fish were retained for carcass analysis. Fish were decapitatedhomogenized in blender, stored in polyethylene bags and frozen forsubsequent ash, protein and lipid analysis. After homogenization, a 15-gsample was oven dried at 1050C for 24h for moisture determination.

Growth performance and feed conversion were measured in terms offinal fish weight, specific growth rate (SGR, %/ d), feed conversion ratio(FCR), feed intake, protein efficiency ratio (PER) and protein productive

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Table 2: Composition and chemical analysis of the experimental diets.

DietsControl 2 3 4 5

Feed compositionFish meal 34 35 35 37 37Soybean meal 25 25 25 25 25Wheat flour 30 15 15Date pits -- 15 151 30 301Corn oil 5 5 5 5 5Vitamin mix.2 3 3 3 3 3Cellulose 3 2 2Chemical analysisDry matter 95.9 94.2 94.7 95.1 94.9Crude protein 40.4 40.4 40.2 41.5 40.3Ether extract 6.7 7.5 7.4 9.0 8.6Crude fiber 4.1 8.7 7.7 11.4 10.5Ash 10.7 10.8 10.4 11.3 10.2NFE 38.1 32.6 34.3 26.8 30.4Gross Ener 18.7 18.8 18.9 19.1 19.1

1) Treated.

value (PPV%). Growth response .and feed utilization parameters werecalculated as follows:

SGR (%/ day) = {In Wj -In Wo) / T} x 100

Where:

Wj is the final body weight of the fish,

Wo is the initial body weight of the fish and

T is the culture period in days

FCR= Total feed fed (g/ fish) / total wet weight gain (g/ fish)

PER= Wet weight gain (g/ fish) / amount of protein fed (g/ fish)

PPV= {Amount of protein fed (g/ fish) / amount of protein retained(g/ fish) x 100

Experimental system:

The feeding trial was conducted in 15 (10 L) fiberglass tanks, in thefish culture laboratory, Faculty of Agricultural Sciences, United ArabEmirates University. The tanks were a part of a complete recirculatingwater system provided with biological and mechanical filters. Continuosaeration was provided by an air blower and air stones. Throughout theexperimental period, water temperature was maintained at 26 :!:10 C byusing thermostatic electrical heater. The water in the system was partiallyexchanged at a rate of 5% daily. Each tank was supplied with water at a rateof 3 L/ min.

Chemical analysis:

Chemical analyses of the experimental diets and fish body wereperfonned according to the standard methods of AOAC (1984). Thenitrogen free extract (NFE) was calculated by difference {100 - (crudeprotein + crude fat + crude fiber + ash)}. Gross energy was calculated basedon the conversion factors: protein 23.27 kJ/ g, lipid 37.67 kJ/ g andcarbohydrate 16.74kJ/ g (Garling & Wilson 1976).

.Statistical analysis:

Data were statistically analyzed by analysis of variance (ANOVA)using the MSTAT4 (Nissen 1987). Duncan's multiple-range test was used","to compare differences among individual mean at P<O.05.

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RESULTS AND DISCUSSION

Replacement of 100% of wheat flour in the diets of Oreoehromisnilotieus fish by untreated date pits (diet 5) reduced significantly (P<0.05)weight gain % and SGR. However, the differences between gain of groups(control, 2,3 and 4) were not significant (P>0.05). Fish group received diet3, where 50% of the wheat flour was replaced by treated date pits showedthe highest growth values. It seems that sulfuric acid treatment had reducedthe crude fiber content of the date pits which consequence increases theutilization of the diets. Vandepopuliere et al. (1995) concluded that highfiber content in diets of monogastric animals decreases their weight gain.Also Belal and AI-Jasser (1996) found that with increasing the inclusionrate of date by-products up to 30%, instead of corn flower in Oreoehromisni/otreus diets, fish weight gain was increased significantly (P<0.05). Theysuggested a certain dietary ratio between complex and simple sugar of3:1for best performance of tilapia fish. This may explain the reduction ofweight gain obtained in the present study when untreated date pits (highfiber content) was the only source of carbohydrate in fish feeds (diet 4).Shiau and Lin (1993) concluded that tilapia fish utilizes complexcarbohydrate (starch) more readily than those simple sugars. Feedconversion (FCR) showed better significant (P<0.05) values in group 3followed by control, diet 2 and 5 than group 4 which showed the highestsignificant (P<0.05) FCR values. However, with replacement of 100%wheat flour by untreated date pits, significant reduction (P<0.05) in feedutilization parameters, with treating the same replacement level with 70%sulfuric acid, utilization of the carbohydrate source was improved.

Protein utilization values of group 3 (1.5% treated date pits) wassuperior significantly (P<0.05) on all other fish groups including thecontrol. More than 15% date pits in the diets decrease the utilization valuesof the dietary protein. Belal and AI-Jasser (1996) found that incorporatingwasted date in tilapia feeds improved the protein sparing effect of fat andcarbohydrate during protein synthesis.

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Chemical compositions of fish body are presented in table 4. . In allgroups including date pits in the diets improved fish body protein content.Fish fed diet 5 (30% treated date pits) showed the highest protein content.Elgasim et al. (1995) explained the protein deposition in animal tissue may

. due to the honnonal effect of date pits as a repartitioning agent (acts in asimilar way as estrogen) which alter the energy deposition towards proteinand away from fat.

Generally, lower percentage of body fat was observed by increasingthe treated date pits percentage in the diets.

In conclusion, the present experiment showed that treated date pitswith sulfuric acid could be utilized in Oreochromis ni/oticus diets up to30% with out adverse effects on its utilization as an available carbohydratesource in fish feeds.

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Table 3: Perfonnance of Oreochromis ni/otic us fingerlings fed the

experimental diets

DietsControl 2 3 4 5 :f: SE

Initial wt. 6.61 6.58 6.61 6.59 6.63 0.04Final wt. 13.97a 13.54a 14.92a 11.25b 13.10ab 0.62

Gain (g/ fish) 7.35a 6.96a 8.31a 4.76b 6.47 ab 0.63

. Weight gain (%)1 114.17a 105.80a 125.70a 72.17b 97.53 ab 10.0SGR2 1.7700 1.72a 1.94a 1.43b 1.61 ab 0.11Feed intake 15.98a 15.85ab 16.39a 14.84 b 15.58 ab 0.31FCR3 2.23b 2.30b 1.98 b 3.22a 2.45 ab 0.23PER4 1.05be 1.19ab 1.33a 0.83 e 1.04 be 0.08PPVs 24.01 b 27.58 ab 29.87a 15.85 e 23.82 b 1.68

1) Weight gain % = (Gain! initial wt) x 100

Afifi, M.; Abdou, F. and AI-Sayed, M. (1966) Date stone meal assubstitute for barley in chick rations. Tropical Agriculture, Trinidad, 43:167-170.

AI-Azzawi, 1.1 (1960) The utilization of date pits in poultry diets. In:The proceedings of the First Conference, University of Baghdad, UniversityPress, Baghdad, Iraq. pp. 97-106

Aldosari, M.N.; AI-Hozab, A.A.; Hmeidan, M. and Alothaymeen, I.(1995) Discarded dates and wheat straw as ingredients in the rations ofgrowing sheep. Arab Gulf Journal of Scientific Research, Riyadh, SaudiArabia. 13(1): 123-131.

AI-Hiti, M.K. and Rous, J. (1978) Date waste without stones inbroiler diets. British Poultry Science. 19: 17-19.

Ali, K.T.; Fine, N.C.; Faraj, M. and Sarsam, N.H. (1956) The use ofdate products in the ration of the lactating dairy cow and the water buffalo.Indian Journal of Veterinary Science. 26: 193-201.

AI-Yousef, Y., Belyea, R.L. and Vandepopuliere, J.M. (1986)Sodium hydroxide treatment of date pits. Pages 103-104 in Proceedings ofSecond Symposium on date palms. King Faisal University, AI-Hasa, Saudi

. Arabia.

AOAC (1984). Official Methods for Analysis of the Association ofOfficial Analysis Chemist, 14thedn. Arlington, Virginia.

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Table 4: Carcass composition (% of dry weight) of Oreochromis niloticusfed the experimental diets

Initial Groups

Control 2 3 4 5 :f: SE

Moisture 71.96a 71.40a 70.095 71.80a 68.13c 69.81a 0.36

Crude protein 52.25d 55.07c 56.40c 59.44 b 55.26c 63.52 a 0.37

Lipid 13.69c 14.97b 16.43a 14.63bc 14.77bc 11.56d 0.31

Ash 21.17a 17.50 b 17.79b 18.66b 18.14b 18.37b 0.30

Rest 12.89a 12.44a 9.41c 7.22d 11.83b 6.56c 0.14

REFERENCES

I

Belal, LE.H. and AI-Jasser, M.S. (1996) Replacing dietary starchwith pitted date truit in Nile tilapia Oreochromis ni/oticus (L.) feed.Aquaculture Research, 28: 385-389.

Elgasim, E.A.; AI-Yousef, Y.A. and Humeida, A.M. (1995) Possiblehbnnonal activity of date pits and flesh fed to meat animals. FoodBiochem., 52: 149-152.

Garling, D..L. and Wilson, R.P. (1976) Optimum dietary protein toenergy ratio for channel catfish fingerlings, Icta/urus punctatus. J. Nutr.106: 1368-1375.

Najib, H.; AI-Yousef, Y.M. and Hmeidan, M. (1994) Partialreplacement of corn with dates in layer diets. Journal of Applied AnimalResources. 6: 91-96.

Nissen, O. (1987) MSTAT4 Michigan State University StatisticalPackage. Dept. Of Crop and Soil Science, Michigan State, East Lansing,Michigan.

I~,-

Richter, K. and Becker, M. (1956) Zusammensetzung und Nahrwertvon Datteln und Teilen der Selben nach Versuchen an Wiederkauren und

Schweinen. Ztscher. Tierernaherung Futtennittelkunde 11: 289.

Shiau, S.Y. and Lin, S.E. (1993). Effect of supplemental dietarychromium and vanadium on the utilization of different carbohydrates intilapia Oreochromis ni/oticus x O. aureus. Aquaculture. 110: 321-330.

Vandepopuliere, J.M.; AI-Yousef, Y. and Lyons, J.J. (1995) datesand date pits as ingredients in broiler starting and coturnix quail breederdiets. Poultry Science, 74: 1134-1142.

Yousif, O.M.; Osman, M.F. and Alhadrami, G.A. (1996) Evaluationof dates and date pits as dietary ingredients in tilapia (Oreochromis aureus)diets differing in protein sources. Bioresource Technology. 57: 81-85.

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